The prevalence of psychotic symptoms and paranoid ideation in non-demented population samples aged 70-82 years.

Objectives: Recent population(Q3) studies have reported an approximate 10% prevalence of psychotic symptoms among elderly aged 85 years and older. Psychotic symptoms may be less prevalent among younger elderly. We examined the prevalence of psychotic symptoms in a population-based sample of non-demented elderly aged 70-82 years.

Methods: A systematic Swedish population sample of 894 non-demented elderly (response rate 68%) representing three birth cohorts (340 women and 224 men aged 70 years and 330 women aged 78 and 82 years) was examined using the Comprehensive Psychopathological Rating Scale (CPRS), during a semi-structured psychiatric interview. A key informant interview was also conducted. Psychotic symptoms were classified according to the DSM-IV Glossary of technical terms.

Results: The 1-year prevalence of any psychotic symptom was 0.9% among non-demented women and men aged 70 years, and 1.2% among women aged 78 and 82 years. Psychotic symptoms were not related to sex or age. The prevalence of paranoid ideation was 1.0%. Among women, any paranoid symptom (persecutory delusions or paranoid ideation) was more common in 70-year-olds (2.6%) than in 78-82-year-olds (0.6%) (p = 0.04).

Conclusions: Psychotic symptoms affected only 1% of this non-demented population aged 70, 78 and 82 years, which is lower than the 7-10% previously found among 85- and 95-year-olds. This might reflect a lower prevalence of psychotic symptoms compared to older elderly or secular changes resulting in lower prevalence of psychotic symptoms in later-born birth cohorts.